Dry rub is the way many barbecuists enhance the flavor of their smoke-cooked meat. It can be as simple as the salt and pepper Texas pitmasters use on brisket or a nuclear-fission secret formula containing anything from gunpowder to curry powder. Sugar often is included in the formula because it caramelizes as it heats and creates a glaze on the meat. There are two basic reasons to rub barbecue before it goes into the pit. The first and obvious one is flavor. Some chefs will rub their brisket or rib racks hours before cooking them, creating, in effect, a dry marinade that penetrates the meat. Many hours later, when the meat has cooked, the rub has become a crust clinging to the outside, known as the bark, supercharged with flavor. The second purpose of a thick rub is to encase the meat, shoring up juices that flow as soon as the bark is broken.